The Effect of Gamma Radiation on Collagen

Investigations on the effect of ionizing radiations on proteins have mainly been concerned with soluble proteins. Irradiation of these, either in solution or in the dry state, leads to aggregation and decreased solubility, and at the same time to fragmentation of the protein molecule (1-4). Little detailed information has been published regarding the insoluble fibrous proteins, but in the few investigations carried out irradiation has been found to increase solubility (5-9). The strength of wool fibers decreases and their solubility in alkali has been found to increase on irradiation with soft X-rays (5), neutrons (6), or y-rays (5, 7, 8) after doses of 5 Mrad and above. Perron and Wright (10) report that the electron irradiation of rat-tail tendon with doses of about 1 Mrad causes decrease in intensity of the X-ray pattern, shrinkage, and increased solubility in water. Little (11) found that the crystalline areas of collagen become disordered at relatively low doses compared with silk, keratin, and other proteins. The present investigation has been undertaken with the object of obtaining some information on the effect of y-radiation on collagen. Such information, besides being of general theoretical interest, is of practical importance with respect to the increasing use of ionizing radiation for the sterilization of sutures, bone grafts, etc. Its use has also been suggested in connection with the preservation of skins and the elimination of anthrax infection.